Nothing 'Jr.' about Junior reverb !

Started by petemoore, June 12, 2008, 03:21:28 PM

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petemoore

  It lives !
  The story goes:
  Echo Park got kicked out for...impaired ability to sound good and work right. I had been wanting a 'real' reverb, EP used to be pretty good, not verb but cool while it lasted, which wasn't very long.
  Then: [out of need for time based effect]..
  Valve Junior with impedance mismatch 'sorta' drives reverb input transducer, amp was able to make something out of the output transducer source..'reverb' is born.
  Utilizing the "Jr. 5w Recto's" spare tube socket for the buffer and gain stage [mixer and output recovery, I wired it up kind of like the 6g15 shows, using a PT as the 'OT' for the reverb tank.
  EL84 drives a 490ohm transducer using a 38V from 120v transformer [kinda big].
  The 'science project' [twisted wires and long leads, bad ground dress etc.] worked as expected [great deep reverb tone, very noisy...
  So I mounted the OT, and cleaned everything up [star grounding / shielding / lifting grounds from chassis] that was wired for the test stage, mounted all the isolated jacks etc.
  I don't know how much better this thing would sound with an audio output transformer [instead of the power tranny I cobbled in there], because it can do thick, deep, long reverb, also does that 'tube bulb' thing...thick tone and note bloom sound...very cool !
  There are a couple more places I could put shielded wires and clean even more, but the hum is hardly notcable as it sits...I love it !
  Other than the 'extra' tube, a stock V Jr has...'most' of a reverb circuit [if 8ohm tank input]. I got lucky with my cobbled clone [actually a fine lookin' amp...teeny/cute] because the chassis layout and PT gave me 4 tube sockets [rectifier, output, preamp, 'extra'].
  Pretty cool because I just had all this laying around and now it's a tube reverb unit 8).
 
Convention creates following, following creates convention.

Dragonfly


petemoore

  Lucky !!
  spent late last morning and early this morning working on it, all yesterday installing components [for the tube, a couple panel mounts etc.]...
  fires up clean with huge reverb available...all the verb-adjectives apply...thick, deep, long, bloomy, bright even...it's a huge sound, I think I'll prefer it to 'echo'...even the name rhymes with 'yeccho'...but it was cool for a short while...
  RV-3 was like that too...now just a POS sound comes out of it.
  Pro-Verb did a stand in for a short while, for some reason this one is very hissy sounding.
  And now the Echo Park puts out a touch of 'stink-tone' [glitchy ec choes, bypass lower volume, and overall 'mucky-tone'...doesn't work right, and probably never will again.
  At least with a Tube reverb you have stuff you can work with over the long haul...outperforming these echoes I've been through [as far as consistant performance] is a low bar to have to jump over.
Convention creates following, following creates convention.

DougH

Sounds pretty cool! Yet another use for a valve jr. Forget an amp- build a reverb out of it! :icon_wink:

I don't find delays to be a good substitute for reverb. I'm using my old boss analog delay right now to add some ambience like a reverb, but it actually sounds pretty cheesy with the guitar by itself. In a mix it sounds fine so for now I get away with it. You probably don't want to hear this, but I'm going to replace it with a Verbzilla as soon as I can ( :icon_wink:).

Sorry to hear you had so much trouble with your Echo Park. Mine, as well as my roto-machine and liquiflange have been trouble free. But I mainly use it for syncopated delay stuff, making use of the tap tempo. I just don't think delays work very good for adding "ambience".
"I can explain it to you, but I can't understand it for you."

petemoore

#4
Sounds pretty cool! Yet another use for a valve jr. Forget an amp- build a reverb out of it!
  Too fun building amps, Epi Jr. could be a reverb or could be an amplifier...pretty easy...but sort of a tight fit to have a transducer transformer and a speaker transformer [I would use speaker clamps to 'one or the other' switch the transformers for they intended application], other than the impedance reflection, it's still a 5w recto amp !
I don't find delays to be a good substitute for reverb.
  Neither to I, but dry isn't wet..."~use what you got until the perfect component arrives" [RG].
  I'm using my old boss analog delay right now to add some ambience like a reverb, but it actually sounds pretty cheesy with the guitar by itself.
Remind me not to schpeel about ad length on 'the sound of electronic components'. In a mix it sounds fine so for now I get away with it. You probably don't want to hear this, but I'm going to replace it with a Verbzilla as soon as I can ( ).
  Even the best electronic components sound a little bit like electronic components.
  trick is [besides 'accuracy, effeciency, distortion and etc.] to find and use the ones you like the sound of.
  Sorry to hear you had so much trouble with your Echo Park.
  Kind of a welcome prompt really, too bad though has that diminished function vibe to it.
  Pretty sure this tube deal will be easier to work with.
  It seemed like the first echo park was a little different to begin with...gets hard to tell over span of time, whatever...this things bypass volume changed, that's when it caught something...I'll call it 'phase mis-alignment' for lack tone-core debugging skills.
  Mine, as well as my roto-machine and liquiflange have been trouble free. But I mainly use it for syncopated delay stuff, making use of the tap tempo. I just don't think delays work very good for adding "ambience".
  Who knows maybe the power supply got something bad in it once, and upchucked into the circuit...other than that it pretty much got mounted right on the PB and was subjected to exactly what all the other pedals were subjected to...of course echo Is a much more complicated matter than boost/dist/phase type effects.
  @@Rate, happy is being better off for the loss !
  I just hit 1 note...note...and I say mahnn...that note had the big bloom...
  I'm pretty sure the thick overall tone of the unit [even with reverb calmed down] has to do with the tubes, tube input, recto, pre and amp..all that contributes to the warm tone, seems a lot less brittle than every time delay effect I've had up to this point...quite a few.
Convention creates following, following creates convention.

aron

Cool application. If you want reverb from a commercial pedal, the Verbzilla is just great.

petemoore

  If you want reverb from a commercial pedal, the Verbzilla is just great.
  I haven't tried VZ...has it got room for 4 tubes and some irons in it.  ;D ?
  One main feature I think makes these types of reverbs standouts are the tubes in them.
  Tube input is the high standard in tones to go for, IME.
  ...there are a long list of descriptive adjectives and opinion/facts...tube inputs are where it's at if you got 'em.

 
Convention creates following, following creates convention.

rnfr

i'd love to see some pix and a more detailed explanation of this!

petemoore

  I found a 1.68 and a 1.55v AAA.
  Stuck them in the camera...nothing.
  Steeped them in ~heavy plastic for 30 seconds, tried again.
  Stuck the USB cable in the camera...nada wink.
  ...any ideas how to make the ~camera? do something...
  I'd be more than happy to try any suggestions with it.
   Old cam always was a power hog, but no response with USB isn't good.
  Which is a shame because Bill 'n I made a cute, small cabinet for it. 6x6x14''. Thin red into pre-seal, sand, orange-ish beige. A1 pallet oak. Radiused cut, round end rectangular hole where 'Marshall' might be.
  I started by testing [for working and ratio's], then removing the transformers from an old chassis [after I cleaned it out, drill, pliers, screwdriver, 'chisel 'n hammer' [rivet remover], coarse stainless steel dishpad cleaned the surfaces of the substrates...turns out it was probably the old amp the EL84 and 'x7's came out of...ie typical/common 'old tube hi-fi'' ~50->60's style setup, same tubes as V.Jr!
  I used perfboard on this one, wrapping the leads through edge holes, using them to form 'turret like' structure, not recommended...kind of an artform superceded by more conventional methods...for the big caps, I left 1 bar of insulated stays [what's the word here], and re-used those lugs to mount the PS filter caps to...a ground bar on the other side.
  Valve Jr. is a great amp, transformer lead swap could get me back to driving ~8ohm loads.
  That took care of the driver portion...[once impedance matched to drive ~800ohms] a pretty good swap for the Fender 6g15, except it's using a 6v6, VJ uses EL84...good swap I say.
  You could check my math, I used a power tranny putting out 38v of 11vac...close as I have works fine, both tanks [one marked 490ohm and a big Accutronics 2spring I think is 1475ohms].
  That leaves the bypass buffer and recovery gain stages...the 9pin socket, already there [which it isn't on valve Jr's..ie would require it]  was easy to get heater wires reconnected, then it was just a matter of placement...which put the mix knob at the back, a most 'away from noise' spot, and since I've had fine results with 1point star grounding, decided to stick with that.
  The rest was just connect the dots on teh schematic, still wondering about the tank body grounding which isn't an issue, at all...noise floor is almost like ground.
  I ran the shielded tank wires right out the RCA holes...thanks to RCA or whoever built the chassis, and isolated the output jack, input jack also was already star grouned.
  I just put it in the box Bill 'n I built...perfect fit for the amp cab, it pins the squishy feet [another patented pete discovery, uses bike tire material, saves tubes IMO] down when the angled top [whole top is an angle through the sides...was originally a pedalboard box]. Tanks screwed right to the back. Perfect...I was rooting around for wood stox to build..oh..here's the perfect box with the side clasps, feet, fits on cabs and the amp sits square on the amp and back board of the box! [with it's top off] for setting an amp on [er...I should test for noise first] !
  This amp has been:
  A 5w Rectifier Jr. amp.
  A 5w Talk Box amp.
  Now it's a Jr. Reverb 1, stunning sound, Surf's Up, as far as I can tell it's a top notch reverb, I just need an 'rijonal' to compare it to !
  As far as making one starting with the V.Jr., not really, a workaround would needed for the additional triode/socket and heater supply the reverb requires.
 
 
 
 
Convention creates following, following creates convention.

DougH

There's a project floating around somewhere called a "revibe" that is basically a standalone tube (spring) reverb and tremolo in one box. Some of the ax84 folks have built them and it gets good reviews. That may be a good place to start if people are looking for ideas on how to build this sort of thing.
"I can explain it to you, but I can't understand it for you."

petemoore

There's a project floating around somewhere called a "revibe" that is basically a standalone tube (spring) reverb and tremolo in one box. Some of the ax84 folks have built them and it gets good reviews. That may be a good place to start if people are looking for ideas on how to build this sort of thing.
  That's not funny ! Last night I was thinkin' how good reverb into tremolo can sound !...does it require 'another extra' tube socket for signal processing...that'd mean I would have to resort to SS recto. which means I won't be doing that.
 
Convention creates following, following creates convention.

DougH

Quotethat'd mean I would have to resort to SS recto. which means I won't be doing that.

What makes the difference in a reverb unit? Tube rect only has an advantage in a class a/b push-pull amp if you want 'sag'. Otherwise it's just more heat, more heater current budget, and more real estate...

If it were me, I'd ditch the tube rect and add a tremolo...
"I can explain it to you, but I can't understand it for you."

petemoore

  What makes the difference in a reverb unit? Tube rect only has an advantage in a class a/b push-pull amp if you want 'sag'. Otherwise it's just more heat, more heater current budget, and more real estate...

If it were me, I'd ditch the tube rect and add a tremolo...

  I knew this and thought this right at the point I hit 'submit'..my intention is to be lazy I guess..
  A fair amount of rippin' and re-wrangling to get to reverb/tremolo status, also that recto tube is 'over there'...not exactly where I'd like it placed for wire routings...getting a bit crowded.
  Gambles...I gambled that the reverb would work...and that I'd be able to get a livable noise floor [I 'won']...one-offing something like this is somewhat of a gamble...but since it was really just a tranny swap and wire up another triode...I figured give it a try, a good gamble is one turned to success.
  ...Ok...where's this tremolo schematic / ?
Convention creates following, following creates convention.